Ansible lab setup guide

@amitmund July 11, 2026

Goal: Build a production-like Ansible lab consisting of:

1 Ubuntu Ansible Control Node (Master)

3 Ubuntu Managed Nodes (Clients)

This guide covers installation, SSH setup, inventory, testing, ad-hoc commands, and your first playbook.

Lab Topology

                   +----------------------+
                   |  Control Node        |
                   |----------------------|
                   | Ubuntu 24.04         |
                   | Ansible Installed    |
                   | SSH Private Key      |
                   +----------+-----------+
                              |
          --------------------------------------------
          |                  |                       |
          |                  |                       |
          ▼                  ▼                       ▼
+----------------+  +----------------+   +----------------+
| Managed Node 1 |  | Managed Node 2 |   | Managed Node 3 |
| Ubuntu         |  | Ubuntu         |   | Ubuntu         |
| SSH Server     |  | SSH Server     |   | SSH Server     |
+----------------+  +----------------+   +----------------+

Lab Requirements

Hardware

Component	Recommendation
RAM	2 GB minimum per VM
CPU	2 vCPU
Disk	20 GB
OS	Ubuntu Server 24.04 LTS

Virtualization

Choose one:

VirtualBox
VMware Workstation
Proxmox
KVM/QEMU
Hyper-V
Multipass
LXD

Lab Machines

Hostname	IP Address	Purpose
ansible-master	192.168.1.10	Control Node
ansible-node1	192.168.1.11	Managed Node
ansible-node2	192.168.1.12	Managed Node
ansible-node3	192.168.1.13	Managed Node

Step 1 — Install Ubuntu

Install Ubuntu Server on all four machines.

During installation:

Create user:

devops

Enable

OpenSSH Server

Verify

hostnamectl

Expected

ansible-master

ansible-node1

etc.

Step 2 — Configure Static IP

Edit Netplan

sudo nano /etc/netplan/*.yaml

Example

network:
  version: 2
  ethernets:
    ens33:
      addresses:
        - 192.168.1.10/24
      gateway4: 192.168.1.1
      nameservers:
        addresses:
          - 8.8.8.8
          - 1.1.1.1

Apply

sudo netplan apply

Verify

ip addr

Step 3 — Update All Machines

sudo apt update

sudo apt upgrade -y

Step 4 — Install OpenSSH

Verify

sudo systemctl status ssh

If missing

sudo apt install openssh-server -y

Enable

sudo systemctl enable ssh

sudo systemctl start ssh

Verify

ss -tulpn | grep 22

Step 5 — Verify Connectivity

From Control Node

ping 192.168.1.11

ping 192.168.1.12

ping 192.168.1.13

Step 6 — Install Ansible

Only on

ansible-master

Install

sudo apt update

sudo apt install ansible -y

Verify

ansible --version

Step 7 — Generate SSH Keys

ansible-master

Generate key

ssh-keygen

Accept defaults

Creates

~/.ssh/id_ed25519

~/.ssh/id_ed25519.pub

Step 8 — Copy Public Key

Node 1

ssh-copy-id [email protected]

Node 2

ssh-copy-id [email protected]

Node 3

ssh-copy-id [email protected]

Verify

ssh [email protected]

Should not ask password.

Step 9 — Create Inventory

Create directory

mkdir ~/ansible-lab

cd ~/ansible-lab

Create inventory

nano inventory.ini

Contents

[web]

ansible-node1 ansible_host=192.168.1.11

ansible-node2 ansible_host=192.168.1.12

[database]

ansible-node3 ansible_host=192.168.1.13

[all:vars]

ansible_user=devops

ansible_python_interpreter=/usr/bin/python3

Verify inventory

ansible-inventory -i inventory.ini --list

Step 10 — Test Ansible Connectivity

ansible all -i inventory.ini -m ping

Expected

SUCCESS

Step 11 — Gather Facts

ansible all -i inventory.ini -m setup

Displays

CPU
Memory
Kernel
IP
Architecture
Disk
Hostname
Interfaces

Step 12 — Useful Ad-hoc Commands

Hostname

ansible all -m command -a hostname

Kernel

ansible all -m command -a "uname -r"

Disk

ansible all -m shell -a "df -h"

Memory

ansible all -m shell -a "free -m"

CPU

ansible all -m shell -a "lscpu"

Uptime

ansible all -m shell -a uptime

Current User

ansible all -m shell -a whoami

Step 13 — First Playbook

Create

nano ping.yml

Contents

---
- name: Test Connectivity
  hosts: all

  tasks:

    - name: Ping Hosts
      ansible.builtin.ping:

Run

ansible-playbook -i inventory.ini ping.yml

Step 14 — Install Nginx

Create

nano nginx.yml

---
- name: Install Nginx
  hosts: web
  become: yes

  tasks:

    - name: Install Package
      apt:
        name: nginx
        state: present
        update_cache: yes

Run

ansible-playbook -i inventory.ini nginx.yml

Verify

curl http://192.168.1.11

Step 15 — Create ansible.cfg

nano ansible.cfg

[defaults]

inventory=inventory.ini

host_key_checking=False

forks=10

timeout=30

Now inventory is automatic.

Step 16 — Verify Inventory

ansible all --list-hosts

Directory Structure

ansible-lab/

├── ansible.cfg

├── inventory.ini

├── ping.yml

├── nginx.yml

└── roles/

Useful Ansible Commands

Command	Description
`ansible --version`	Show version
`ansible all -m ping`	Test connectivity
`ansible all -m setup`	Gather facts
`ansible-playbook playbook.yml`	Execute playbook
`ansible-inventory --list`	Show inventory
`ansible-doc apt`	Module documentation
`ansible-galaxy init role`	Create role
`ansible-config dump`	Show configuration
`ansible localhost -m debug -a "msg='Hello'"`	Debug message

Verify SSH

ssh [email protected]

ssh [email protected]

ssh [email protected]

Troubleshooting

Permission Denied

Permission denied (publickey)

Fix

ssh-copy-id [email protected]

Host Unreachable

Check

ping

ip addr

netplan

firewall

Python Missing

Failed to find Python

Install

sudo apt install python3 -y

SSH Timeout

Verify

systemctl status ssh

Inventory Errors

Validate

ansible-inventory -i inventory.ini --list

Security Best Practices

Use SSH keys instead of passwords.
Disable root SSH login.
Disable password authentication after key setup.
Keep Ansible and Ubuntu updated.
Use become: yes only when necessary.
Store secrets in Ansible Vault, not in playbooks.
Restrict SSH access using firewalls or security groups.
Use separate inventories for development, staging, and production.

Exercises

Add a fourth managed node.
Create a new inventory group named monitoring.
Write a playbook to install htop.
Configure passwordless SSH for a new user.
Create a playbook that updates all packages.
Gather and display the kernel version from every node.
Install Docker on all managed nodes using a playbook.
Reboot all managed nodes with Ansible.
Create an Ansible role for Nginx installation.
Encrypt a variable using Ansible Vault.

Interview Questions

What is the difference between the Ansible Control Node and Managed Node?
Why does Ansible use SSH instead of agents?
What is an inventory file?
What are Ansible modules?
What is a playbook?
What is the difference between command, shell, and raw modules?
What is become: yes?
What are Ansible facts?
What is Ansible Vault used for?
How would you organize inventories for multiple environments?

Next Learning Topics

Inventory Groups
Variables
Facts
Playbooks
Modules
Roles
Templates (Jinja2)
Handlers
Tags
Conditionals
Loops
Vault
Collections
Galaxy
Dynamic Inventory
Error Handling
Async Tasks
Delegation
Serial & Rolling Updates
Strategy Plugins
Custom Modules
CI/CD Integration
AWX / Ansible Automation Platform
Production Best Practices

Lab Topology

Lab Requirements

Hardware

Virtualization

Lab Machines

Step 1 — Install Ubuntu

Step 2 — Configure Static IP

Step 3 — Update All Machines

Step 4 — Install OpenSSH

Step 5 — Verify Connectivity

Step 6 — Install Ansible

Step 7 — Generate SSH Keys

Step 8 — Copy Public Key

Step 9 — Create Inventory

Step 10 — Test Ansible Connectivity

Step 11 — Gather Facts

Step 12 — Useful Ad-hoc Commands

Step 13 — First Playbook

Step 14 — Install Nginx

Step 15 — Create ansible.cfg

Step 16 — Verify Inventory

Directory Structure

Useful Ansible Commands

Verify SSH

Troubleshooting

Permission Denied

Host Unreachable

Python Missing

SSH Timeout

Inventory Errors

Security Best Practices

Exercises

Interview Questions

Next Learning Topics

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